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Chapter 56 Conservation Biology and Restoration Ecology PowerPoint® Lecture Presentations for Biology Eighth Edition Neil Campbell and Jane Reece Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Overview: Striking Gold • 1.8 million species have been named and described • Biologists estimate 10–200 million species exist on Earth • Tropical forests contain some of the greatest concentrations of species and are being destroyed at an alarming rate • Humans are rapidly pushing many species toward extinction Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-1 Fig. 56-2 • Conservation biology, which seeks to preserve life, integrates several fields: – Ecology – Physiology – Molecular biology – Genetics – Evolutionary biology Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings • Restoration ecology applies ecological principles to return degraded ecosystems to conditions as similar as possible to their natural state Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Concept 56.1: Human activities threaten Earth’s biodiversity • Rates of species extinction are difficult to determine under natural conditions • The high rate of species extinction is largely a result of ecosystem degradation by humans • Humans are threatening Earth’s biodiversity Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Three Levels of Biodiversity • Biodiversity has three main components: – Genetic diversity – Species diversity – Ecosystem diversity Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-3 Genetic diversity in a vole population Species diversity in a coastal redwood ecosystem Community and ecosystem diversity across the landscape of an entire region Genetic Diversity • Genetic diversity comprises genetic variation within a population and between populations Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Species Diversity • Species diversity is the variety of species in an ecosystem or throughout the biosphere • According to the U.S. Endangered Species Act: – An endangered species is “in danger of becoming extinct throughout all or a significant portion of its range” – A threatened species is likely to become endangered in the foreseeable future Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings • Conservation biologists are concerned about species loss because of alarming statistics regarding extinction and biodiversity • Globally, 12% of birds, 20% of mammals, and 32% of amphibians are threatened with extinction Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-4 (a) Philippine eagle (b) Yangtze River dolphin (c) Javan rhinoceros Fig. 56-4a (a) Philippine eagle Fig. 56-4b (b) Yangtze River dolphin Fig. 56-4c (c) Javan rhinoceros Ecosystem Diversity • Human activity is reducing ecosystem diversity, the variety of ecosystems in the biosphere • More than 50% of wetlands in the contiguous United States have been drained and converted to other ecosystems Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-5 Biodiversity and Human Welfare • Human biophilia allows us to recognize the value of biodiversity for its own sake • Species diversity brings humans practical benefits Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Benefits of Species and Genetic Diversity • In the United States, 25% of prescriptions contain substances originally derived from plants • For example, the rosy periwinkle contains alkaloids that inhibit cancer growth Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-6 • The loss of species also means loss of genes and genetic diversity • The enormous genetic diversity of organisms has potential for great human benefit Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Ecosystem Services • Ecosystem services encompass all the processes through which natural ecosystems and their species help sustain human life • Some examples of ecosystem services: – Purification of air and water – Detoxification and decomposition of wastes – Cycling of nutrients – Moderation of weather extremes Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Three Threats to Biodiversity • Most species loss can be traced to three major threats: – Habitat destruction – Introduced species – Overexploitation Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Habitat Loss • Human alteration of habitat is the greatest threat to biodiversity throughout the biosphere • In almost all cases, habitat fragmentation and destruction lead to loss of biodiversity • For example – In Wisconsin, prairie occupies <0.1% of its original area – About 93% of coral reefs have been damaged by human activities Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-7 Introduced Species • Introduced species are those that humans move from native locations to new geographic regions • Without their native predators, parasites, and pathogens, introduced species may spread rapidly • Introduced species that gain a foothold in a new habitat usually disrupt their adopted community Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings • Sometimes humans introduce species by accident, as in case of the brown tree snake arriving in Guam as a cargo ship “stowaway” Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-8 (a) Brown tree snake (b) Kudzu Fig. 56-8a (a) Brown tree snake Fig. 56-8b (b) Kudzu • Humans have deliberately introduced some species with good intentions but disastrous effects • An example is the introduction of kudzu in the southern United States Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Overexploitation • Overexploitation is human harvesting of wild plants or animals at rates exceeding the ability of populations of those species to rebound • Overexploitation by the fishing industry has greatly reduced populations of some game fish, such as bluefin tuna Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-9 • DNA analysis can help conservation biologists to identify the source of illegally obtained animal products Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Concept 56.2: Population conservation focuses on population size, genetic diversity, and critical habitat • Biologists focusing on conservation at the population and species levels follow two main approaches: – The small-population approach – The declining-population approach Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Small-Population Approach • The small-population approach studies processes that can make small populations become extinct Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Extinction Vortex • A small population is prone to positivefeedback loops that draw it down an extinction vortex • The key factor driving the extinction vortex is loss of the genetic variation necessary to enable evolutionary responses to environmental change Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-10 Small population Inbreeding Genetic drift Lower reproduction Higher mortality Loss of genetic variability Reduction in individual fitness and population adaptability Smaller population Case Study: The Greater Prairie Chicken and the Extinction Vortex • Populations of the greater prairie chicken were fragmented by agriculture and later found to exhibit decreased fertility • To test the extinction vortex hypothesis, scientists imported genetic variation by transplanting birds from larger populations • The declining population rebounded, confirming that low genetic variation had been causing an extinction vortex Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-11 RESULTS Number of male birds 200 150 100 Translocation 50 0 1970 1975 1980 1985 Year 1990 1995 (a) Population dynamics Eggs hatched (%) 100 90 80 70 60 50 40 30 1970–’74 ’75–’79 ’80–’84 ’85–’89 Years (b) Hatching rate ’90 ’93–’97 Fig. 56-11a RESULTS Number of male birds 200 150 100 Translocation 50 0 1970 1975 (a) Population dynamics 1980 1985 Year 1990 1995 Fig. 56-11b RESULTS Eggs hatched (%) 100 90 80 70 60 50 40 30 1970–’74 ’75–’79 ’80–’84 ’85–’89 Years (b) Hatching rate ’90 ’93–’97 Minimum Viable Population Size • Minimum viable population (MVP) is the minimum population size at which a species can survive • The MVP depends on factors that affect a population’s chances for survival over a particular time Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Effective Population Size • A meaningful estimate of MVP requires determining the effective population size, which is based on the population’s breeding potential Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings • Effective population size Ne is estimated by: Ne = 4NfNm Nf + N m – where Nf and Nm are the number of females and the number of males, respectively, that breed successfully Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Case Study: Analysis of Grizzly Bear Populations • One of the first population viability analyses was conducted as part of a long-term study of grizzly bears in Yellowstone National Park • This grizzly population is about 400, but the Ne is about 100 • The Yellowstone grizzly population has low genetic variability compared with other grizzly populations Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings • Introducing individuals from other populations would increase the numbers and genetic variation Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-12 Declining-Population Approach • The declining-population approach – Focuses on threatened and endangered populations that show a downward trend, regardless of population size – Emphasizes the environmental factors that caused a population to decline Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Steps for Analysis and Intervention • The declining-population approach involves several steps: – Confirm that the population is in decline – Study the species’ natural history – Develop hypotheses for all possible causes of decline – Test the hypotheses in order of likeliness – Apply the results of the diagnosis to manage for recovery Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Case Study: Decline of the Red-Cockaded Woodpecker • Red-cockaded woodpeckers require living trees in mature pine forests • They have a complex social structure where one breeding pair has up to four “helper” individuals • This species had been forced into decline by habitat destruction Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-13 Red-cockaded woodpecker (a) Forests with low undergrowth (b) Forests with high, dense undergrowth Fig. 56-13a (a) Forests with low undergrowth Fig. 56-13b (b) Forests with high, dense undergrowth Fig. 56-13c Red-cockaded woodpecker • In a study where breeding cavities were constructed, new breeding groups formed only in these sites • Based on this experiment, a combination of habitat maintenance and excavation of breeding cavities enabled this endangered species to rebound Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Weighing Conflicting Demands • Conserving species often requires resolving conflicts between habitat needs of endangered species and human demands • For example, in the U.S. Pacific Northwest, habitat preservation for many species is at odds with timber and mining industries • Managing habitat for one species might have positive or negative effects on other species Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Concept 56.3: Landscape and regional conservation aim to sustain entire biotas • Conservation biology has attempted to sustain the biodiversity of entire communities, ecosystems, and landscapes • Ecosystem management is part of landscape ecology, which seeks to make biodiversity conservation part of land-use planning Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Landscape Structure and Biodiversity • The structure of a landscape can strongly influence biodiversity Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fragmentation and Edges • The boundaries, or edges, between ecosystems are defining features of landscapes • Some species take advantage of edge communities to access resources from both adjacent areas Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-14 (a) Natural edges (b) Edges created by human activity Fig. 56-14a (a) Natural edges Fig. 56-14b (b) Edges created by human activity • The Biological Dynamics of Forest Fragments Project in the Amazon examines the effects of fragmentation on biodiversity • Landscapes dominated by fragmented habitats support fewer species due to a loss of species adapted to habitat interiors Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-15 Corridors That Connect Habitat Fragments • A movement corridor is a narrow strip of quality habitat connecting otherwise isolated patches • Movement corridors promote dispersal and help sustain populations • In areas of heavy human use, artificial corridors are sometimes constructed Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-16 Establishing Protected Areas • Conservation biologists apply understanding of ecological dynamics in establishing protected areas to slow the loss of biodiversity • Much of their focus has been on hot spots of biological diversity Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Finding Biodiversity Hot Spots • A biodiversity hot spot is a relatively small area with a great concentration of endemic species and many endangered and threatened species • Biodiversity hot spots are good choices for nature reserves, but identifying them is not always easy Video: Coral Reef Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-17 Terrestrial biodiversity hot spots Equator Marine biodiversity hot spots Philosophy of Nature Reserves • Nature reserves are biodiversity islands in a sea of habitat degraded by human activity • Nature reserves must consider disturbances as a functional component of all ecosystems Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings • An important question is whether to create fewer large reserves or more numerous small reserves • One argument for extensive reserves is that large, far-ranging animals with low-density populations require extensive habitats • Smaller reserves may be more realistic, and may slow the spread of disease throughout a population Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-18 0 50 100 Kilometers Yellow stone R. MONTANA Yellowstone one h s National Sho Park IDAHO ak eR . IDAHO Sn Grand Teton National Park WYOMING MONTANA R. WYOMING Biotic boundary for short-term survival; MVP is 50 individuals. Biotic boundary for long-term survival; MVP is 500 individuals. Zoned Reserves • The zoned reserve model recognizes that conservation often involves working in landscapes that are largely human dominated • A zoned reserve includes relatively undisturbed areas and the modified areas that surround them and that serve as buffer zones • Zoned reserves are often established as “conservation areas” • Costa Rica has become a world leader in establishing zoned reserves Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-19 Nicaragua CARIBBEAN SEA Costa Rica National park land Pa na ma Buffer zone PACIFIC OCEAN (a) Zoned reserves in Costa Rica (b) Schoolchildren in one of Costa Rica’s reserves Fig. 56-19a Nicaragua CARIBBEAN SEA Costa Rica National park land Pa na ma Buffer zone PACIFIC OCEAN (a) Zoned reserves in Costa Rica Fig. 56-19b (b) Schoolchildren in one of Costa Rica’s reserves • Some zoned reserves in the Fiji islands are closed to fishing, which actually improves fishing success in nearby areas • The United States has adopted a similar zoned reserve system with the Florida Keys National Marine Sanctuary Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-20 GULF OF MEXICO FLORIDA Florida Keys National Marine Sanctuary 50 km Concept 56.4: Restoration ecology attempts to restore degraded ecosystems to a more natural state • Given enough time, biological communities can recover from many types of disturbances • Restoration ecology seeks to initiate or speed up the recovery of degraded ecosystems • A basic assumption of restoration ecology is that most environmental damage is reversible • Two key strategies are bioremediation and augmentation of ecosystem processes Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-21 (a) In 1991, before restoration (b) In 2000, near the completion of restoration Fig. 56-21a (a) In 1991, before restoration Fig. 56-21b (b) In 2000, near the completion of restoration Bioremediation • Bioremediation is the use of living organisms to detoxify ecosystems • The organisms most often used are prokaryotes, fungi, or plants • These organisms can take up, and sometimes metabolize, toxic molecules Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-22 Concentration of soluble uranium (µM) 6 5 4 3 2 1 0 0 (a) Unlined pits filled with wastes containing uranium 50 100 150 200 250 300 Days after adding ethanol (b) Uranium in groundwater 350 400 Fig. 56-22a (a) Unlined pits filled with wastes containing uranium Fig. 56-22b Concentration of soluble uranium (µM) 6 5 4 3 2 1 0 0 50 100 150 200 250 300 350 Days after adding ethanol (b) Uranium in groundwater 400 Biological Augmentation • Biological augmentation uses organisms to add essential materials to a degraded ecosystem • For example, nitrogen-fixing plants can increase the available nitrogen in soil Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Exploring Restoration • The newness and complexity of restoration ecology require that ecologists consider alternative solutions and adjust approaches based on experience Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-23a Equator Fig. 56-23b Truckee River, Nevada Fig. 56-23c Kissimmee River, Florida Fig. 56-23d Tropical dry forest, Costa Rica Fig. 56-23e Rhine River, Europe Fig. 56-23f Succulent Karoo, South Africa Fig. 56-23g Coastal Japan Fig. 56-23h Maungatautari, New Zealand Concept 56.5: Sustainable development seeks to improve the human condition while conserving biodiversity • The concept of sustainability helps ecologists establish long-term conservation priorities Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Sustainable Biosphere Initiative • Sustainable development is development that meets the needs of people today without limiting the ability of future generations to meet their needs • The goal of the Sustainable Biosphere Initiative is to define and acquire basic ecological information for responsible development, management, and conservation of Earth’s resources Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings • Sustainable development requires connections between life sciences, social sciences, economics, and humanities Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Case Study: Sustainable Development in Costa Rica • Costa Rica’s conservation of tropical biodiversity involves partnerships between the government, other organizations, and private citizens • Human living conditions (infant mortality, life expectancy, literacy rate) in Costa Rica have improved along with ecological conservation Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-24 80 Life expectancy Infant mortality 70 150 60 100 50 50 40 0 30 1900 1950 Year 2000 Life expectancy (years) Infant mortality (per 1,000 live births) 200 The Future of the Biosphere • Our lives differ greatly from early humans who hunted and gathered and painted on cave walls Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-25 (a) Detail of animals in a 36,000-year-old cave painting, Lascaux, France (b) A 30,000-year-old ivory carving of a water bird, found in Germany (c) Biologist Carlos Rivera Gonzales examining a tiny tree frog in Peru Fig. 56-25a (a) Detail of animals in a 36,000-year-old cave painting, Lascaux, France Fig. 56-25b (b) A 30,000-year-old ivory carving of a water bird, found in Germany Fig. 56-25c (c) Biologist Carlos Rivera Gonzales examining a tiny tree frog in Peru • Our behavior reflects remnants of our ancestral attachment to nature and the diversity of life— the concept of biophilia • Our sense of connection to nature may motivate realignment of our environmental priorities Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 56-UN1 Genetic diversity: source of variations that enable populations to adapt to environmental changes Species diversity: important in maintaining structure of communities and food webs Ecosystem diversity: Provide life-sustaining services such as nutrient cycling and waste decomposition Fig. 56-UN2 You should now be able to: 1. Distinguish between conservation biology and restoration biology 2. List the three major threats to biodiversity and give an example of each 3. Define and compare the small-population approach and the declining-population approach 4. Distinguish between the total population size and the effective population size Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 5. Describe the conflicting demands that may accompany species conservation 6. Define biodiversity hot spots and explain why they are important 7. Define zoned reserves and explain why they are important 8. Explain the importance of bioremediation and biological augmentation of ecosystem processes in restoration efforts Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 9. Describe the concept of sustainable development 10. Explain the goals of the Sustainable Biosphere Initiative Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings